A beard trimmer is a hand-held electronic device used to cut a man's beard to a specific length. It usually features multiple length settings that can vary from one-tenth of an inch (0.25 cm) to one-half inch (1.27 cm). The tool functions by using several sets of thin metal blades tipped with teeth. These blades are typically one inch (2.54 cm) wide, and are stacked on top of one another. They oscillate when the trimmer is turned on, causing the teeth to periodically overlap.
When placed against the face, the oscillating blades will cut any hair they come in contact with. A beard trimmer generally has a plastic guard that will snap over the end of the blades, preventing them from touching the skin directly. The guard will be controlled by a switch or wheel on the trimmer, most often found on the side of the device. This allows the user to set the distance from the skin that hair will be cut.
This feature also allows the trimmer to be used to create or maintain several different styles of facial hair. If the guard is placed at the setting closest to the blades, the beard trimmer can be used to maintain a scruffy or five o'clock shadow look, in which the hair is merely stubble. When the guard is set to the farthest distance from the blades, the trimmer can be used to maintain a full beard, by cutting off only very long or unruly hairs.
A men's beard trimmer is usually made of plastic, and has stainless steel blades. Most trimmers are battery powered, and many models now feature a rechargeable battery that charges when the trimmer is placed on a power dock. Other features can include a vacuum, which can be used to clean up hair around the sink after the grooming is complete.
Included with a beard trimmer will also be a small comb and brush. This comb can be used for beard maintenance, or as a length guide if the user prefers to trim their beard without the guard in place. The brush is used to clean the blades, and most trimmers will have an option to lift the blades up, allowing trapped hair to be cleaned out.
Beard trimmers are also marketed as hair trimmers, and can be used to shorten hair on the head. Many will feature double motors or extra battery life for this purpose. In order to use a beard trimmer on the head, the key is to start with the guard at the greatest distance from the blade, run the trimmer over the entire area needing to be trimmed, and then adjust if necessary. Using too short a distance initially will simply clog the blade mechanism.